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/*
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* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
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* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*/
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// package java.util;
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import java.math.BigInteger;
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import java.util.stream.DoubleStream;
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import java.util.stream.IntStream;
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import java.util.stream.LongStream;
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/**
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* The {@code StreamableRng} interface augments the {@code Rng} interface
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* to provide methods that return streams of {@code Rng} objects.
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* Ideally, such a stream of objects would have the property that the
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* behavior of each object is statistically independent of all the others.
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* In practice, one may have to settle for some approximation to this property.
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*
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* A generator that implements interface {@link java.util.SplittableRng}
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* may choose to use its {@code splits} method to implement the {@code rngs}
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* method required by this interface.
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*
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* A generator that implements interface {@link java.util.JumpableRng}
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* may choose to use its {@code jumps} method to implement the {@code rngs}
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* method required by this interface.
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*
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* A generator that implements interface {@link java.util.LeapableRng}
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* may choose to use its {@code leaps} method to implement the {@code rngs}
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* method required by this interface.
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*
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* <p>An implementation of the {@code StreamableRng} interface must provide
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* concrete definitions for the methods {@code nextInt()}, {@code nextLong},
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* {@code period()}, and {@code rngs()}.
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* Default implementations are provided for all other methods.
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*
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* <p>Objects that implement {@code java.util.StreamableRng} are typically
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* not cryptographically secure. Consider instead using
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* {@link java.security.SecureRandom} to get a cryptographically
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* secure pseudo-random number generator for use by
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* security-sensitive applications.
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*
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* @author Guy Steele
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* @since 1.9
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*/
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import java.util.stream.Stream;
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interface StreamableRng extends Rng {
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/**
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* Returns an effectively unlimited stream of objects, each of
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* which implements the {@code Rng} interface. Ideally the
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* generators in the stream will appear to be statistically
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* independent. The new generators should be of the same kind
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* as this generator.
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*
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* @implNote It is permitted to implement this method in a manner
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* equivalent to {@code rngs(Long.MAX_VALUE)}.
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*
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* @return a stream of objects that implement the {@code Rng} interface
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*/
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Stream<Rng> rngs();
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/**
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* Returns an effectively unlimited stream of objects, each of
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* which implements the {@code Rng} interface. Ideally the
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* generators in the stream will appear to be statistically
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* independent. The new generators should be of the same kind
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* as this generator.
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*
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* @implNote The default implementation calls {@code rngs()} and
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* then limits its length to {@code streamSize}.
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*
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* @param streamSize the number of generators to generate
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* @return a stream of objects that implement the {@code Rng} interface
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* @throws IllegalArgumentException if {@code streamSize} is
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* less than zero
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*/
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default Stream<Rng> rngs(long streamSize) {
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RngSupport.checkStreamSize(streamSize);
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return rngs().limit(streamSize);
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}
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}
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